"Fuma no Kojirou: Seiken Sensou-hen" is a two-episode OVA series that serves as a continuation of the original "Fuma no Kojirou" story, adapting the "Seiken Sensou" arc from the manga. The narrative centers on Kojirou Fuma, a young ninja from the Fuma clan, who becomes embroiled in a high-stakes battle involving ancient swords and rival ninja factions. The story begins with Kojirou being summoned by the Yagyu clan, a powerful ninja group, to participate in a deadly tournament. The Yagyu clan seeks to retrieve the legendary Seiken, or Holy Swords, which are said to grant immense power to their wielder. These swords are scattered across the land, and the tournament is a means to gather the strongest warriors to retrieve them.

Kojirou is joined by his loyal companions, including his childhood friend and fellow Fuma clan member, Shiranui, and the enigmatic Yasha, a skilled warrior with her own motives. Together, they face off against formidable opponents from various ninja clans, each vying for control of the Seiken. The tournament is not merely a test of strength but also a strategic battle, as alliances shift and betrayals unfold. The Yagyu clan, led by the cunning and ruthless Jubei Yagyu, manipulates the participants to further their own agenda, which involves using the Seiken to dominate the ninja world.

As the battles progress, Kojirou’s resolve and skills are put to the test. He confronts powerful adversaries, including the deadly Yagyu swordsmen and other ninja clans with their own unique abilities. The narrative delves into themes of loyalty, honor, and the cost of power, as Kojirou grapples with the moral implications of the Seiken’s destructive potential. The climax of the series revolves around a final confrontation between Kojirou and Jubei Yagyu, where the true nature of the Seiken and the Yagyu clan’s ambitions are revealed.

The OVA maintains a fast-paced and action-driven narrative, with a focus on intense sword fights and ninja techniques. Kojirou’s growth as a warrior and his unwavering commitment to his clan’s values are central to the story, while the supporting characters add depth to the conflict. The series concludes with an open-ended resolution, leaving room for further exploration of the Fuma clan’s legacy and the ongoing struggle for the Seiken.